This application relates to an optical measuring instrument for optically detecting a specimen using a flow channel. More particularly, the present application relates to an optical measuring instrument for optically detecting a specimen which circulates in a flow channel, a wavelength calibration method for a light detector for use with an optical measuring instrument and an optical measuring method which uses a wavelength calibration method.
In recent years, together with the development of the analysis method, a method has been and is being developed wherein organic fine particles such as cells and microorganisms or fine particles such as micro beads are circulated in a flow channel and, during such circulation, the fine particles are measured individually and the measured fine particles are analyzed or sorted. Technical improvement of the analysis method called flow cytometry as a representative example of such a method of analysis or dispensing of fine particles using a flow channel is progressing rapidly.
The flow cytometry is an analysis method wherein fine particles of an object of analysis are fed into fluid to form a train of the fine particles and a laser beam or the like is irradiated upon the lined up fine particles to detect fluorescent light or scattered light generated from the fine particles to analyze the fine particles and further carry out sorting of the fine particles based on a result of the analysis.
Since an apparatus which carries out the flow cytometry is disadvantageous in that it is large in size and low in general-purpose properties, a method which uses a microchip wherein a fine flow channel is formed in a substrate made of an inorganic material such as silicon or glass or a high-molecular material such as plastics has been proposed in recent years.
For example, a fine particle sorting microchip has been proposed and disclosed in Japanese Patent Laid-Open No. 2003-107099 (hereinafter referred to as Patent Document 1). The fine particle sorting microchip disclosed in Patent Document 1 includes a substrate and several elements provided on the substrate and at least including an introduction flow channel for introducing solution containing fine particles, a sheath flow forming flow channel disposed at least on one side of the introduction flow channel, a fine particle measuring part for measuring the fine particles introduced thereto, two or more fine particle sorting flow channels disposed on the downstream with respect to the file particle measuring parts for sorting and recovering the fine particles, and two or more electrodes located in the proximity of flow channel ports from the fine particle measuring parts to the fine particle sorting flow channels for controlling the moving direction of the fine particles.
Meanwhile, a cell analyzing and separating apparatus has been proposed and is disclosed in Japanese Patent Laid-Open No. 2004-85323 (hereinafter referred to as Patent Document 2). The cell analyzing and separating apparatus disclosed in Patent Document 2 includes a flow channel into which fluid containing a specimen to be introduced in laminar flows into a specimen sorting section is introduced, a pair of flow channels disposed symmetrically on the opposite sides of the flow channel for allowing only the fluid to be introduced thereinto, means for introducing external force into the specimen sorting section only when the observation specimen is to be discharged from the specimen sorting section, a specimen recovering flow channel disposed on the downstream side of the flow channel into which the specimen is introduced so that the fluid containing the specimen from which only the selected specimen is recovered in laminar flows from the specimen sorting section, and a pair of fluid paths disposed symmetrically on the opposite sides of the specimen recovering flow channel for receiving the unnecessary specimen discharged thereinto.
Incidentally, wavelength calibration of a light detector used in optical measurement in which a flow channel is used is generally carried out such that a light source which emits light of a bright line spectrum is used to irradiate the light in advance on a flow channel before a specimen is circulated in the flow channel and the light is measured by the light detector to carry out the wavelength calibration.